Lebanese group says top commander Badreddine killed by fire from from a Sunni armed group in Syria.

Hezbollah has said its top military commander Mustafa Badreddine died as a result of artillery shelling by a Sunni armed group in Damascus.

The Lebanese Shia group announced Badreddine's death on Friday and a military funeral was held for him on the same day in southern Beirut.

"Investigations have showed that the explosion, which targeted one of our bases near Damascus International Airport, and which led to the martyrdom of commander Mustafa Badreddine, was the result of artillery bombardment carried out by takfiri groups," Hezbollah said in a statement.

Hezbollah earlier said it was working to "define the nature of the explosion and its cause, and whether it was the result of an air strike, or missile [attack] or artillery".

Badreddine, 55, was one of the highest ranking officials in the group, and believed to be responsible for its operations in Syria, where thousands of its members are fighting alongside Syrian President Bashar al-Assad.